General Site Information

As of March 19, 2019, data on bat guano-harvester interactions is available for 3 countries : Myanmar, Democratic Republic of Congo, Viet Nam. All are PREDICT sites except Kimpese/Weene in the Democratic Republic of Congo.

Site Name Country Type
Buffalo Cave Myanmar cave
Lino Cave Myanmar cave
Saddan Cave Myanmar cave
Kimpese/Weene Democratic Republic of Congo cave
Cao Lanh City, Dong Thap Province 1 Viet Nam farm
Cao Lanh City, Dong Thap Province 2 Viet Nam farm
Taii Lap Comm., Huu Lung District, Lang Son Province Viet Nam cave

5 of the 7 sites are at the cave interface, where bat guano is harvested from fecal matter of bats roosting in caves. Only caves were access-controlled, with some sites (Myanmar) primarly functioning as a religious temple, while others required a permit or verbal permission to enter. Other interesting variables for cave sites include cave height, degree of light penetration, degree of water coverage, and ease of cave navigation.

2 of the 7 sites are at the farm interface, where bat guano is harvested from artificial roosts set up below tree-like structures (Fig. 1, below). Both farm sites had artifical roosts composed of sugar palm leaves.

Figures 1-2. Guano farm site, Viet Nam

Bats were present during harvest at all sites. Most roosts were 1,000 - 5,000 bats in size, except the Viet Nam cave site where there were over 100,000 bats, potentially as high as 3 million depending on the season.

Fig 2. Roost sizes across sites

Fig 2. Roost sizes across sites

Harvesters

The DRC and Vietnam cave sites had the highest number of harvesters, and some of the highest frequencies of harvest. All Viet Nam sites were harvested frequently, both at cave and farm sites.

Site Name Number of Harvesters Duration of Harvesting Frequency of Harvesting
MMR-Cave-1 3 210 minutes 1 time per year
MMR-Cave-2 7 120 minutes 3 times per month
MMR-Cave-3 4 120 minutes 2 times per year
DRC-Cave-1 50 30 minutes 3 times per week
VNM-Farm-1 1 20 minutes 2 times per week
VNM-Farm-2 2 20 minutes daily
VNM-Cave-1 30 180 minutes daily

All harvesters were local in origin, although Myanmar Caves 2 and 3 also had seasonal harvesters come in. Non-harvesters were present at the guano harvesting areas for all sites except the DRC cave; this included locals at all sites, children at all Myanmar sites and at the Viet Nam Cave site, and 10-20 tourists per day at Myanmar Cave 3 (Saddan Cave) site. Limits to harvesting included bat migration elsewhere (5/7 sites), high water levels (2 cave sites), low demand (2 cave sites) , and hunting of bats for food by locals (cave and farm site in Viet Nam).

Activities at all sites included harvesting, packaging, and storing guano. Selling guano also occurred at all Myanmar and Viet Nam sites.

Guano

Sites in Myanmar were harvested the least frequently, ranging from 3 times/month to once a year. Despite this, MMR-Cave-2 (Buffalo Cave) had the highest collection volume at approximately 54,000 kg annually. Collection occured daily or several times a week at the DRC and Viet Nam sites, with volumes ranging from 312 - 3000 kg collected per year.

Exposure and Risk

Individual Exposures
Population Exposures
Site Name Frequency of Harvesting (days per year) Duration of Harvesting (hours per year) Guano Collected (kg per person per year) Guano Exposures Collection Exposures PPE Exposures WASH Exposures Months Harvested Number of Harvesters Total Guano Collected (kg)
MMR-Cave-1 1 4 400 0.50 some using shovels; some using spades; some using brooms; some using only hands none using gloves; none wearing makeshift mask; none wearing goggles; none wearing shoes; none wearing clothing for harvesting; none wearing mask some washing; all using soap; all washing shoes; all washing feet; all washing hands; all washing body once a year 3 1,200
MMR-Cave-2 24 48 3,120 0.50 some using shovels; some using spades; some using brooms; some using only hands none using gloves; none wearing makeshift mask; none wearing goggles; none wearing shoes; none wearing clothing for harvesting; none wearing mask some washing; none using soap; all washing shoes; all washing feet; all washing hands; all washing body Jan-Mar, Nov-Dec 7 21,840
MMR-Cave-3 3 6 5,000 0.50 some using shovels; some using spades; some using brooms; none using only hands none using gloves; all wearing makeshift mask; none wearing goggles; none wearing shoes; none wearing clothing for harvesting; none wearing mask some washing; none using soap; all washing shoes; all washing feet; all washing hands; all washing body Mar-May, Nov-Dec 4 20,000
DRC-Cave-1 156 78 200 0.33 none using shovels; none using spades; none using brooms; none using only hands none using gloves; none wearing makeshift mask; none wearing goggles; none wearing shoes; none wearing clothing for harvesting; none wearing mask none washing; none using soap; none washing shoes; none washing feet; all washing hands; all washing body May-Aug 50 10,000
VNM-Farm-1 104 35 156 0.33 all using shovels; none using spades; none using brooms; all using only hands none using gloves; none wearing makeshift mask; none wearing goggles; all wearing shoes; all wearing clothing for harvesting; some wearing mask some washing; all using soap; none washing shoes; none washing feet; none washing hands; all washing body Jan-Dec 1 156
VNM-Farm-2 365 122 876 0.17 all using shovels; none using spades; none using brooms; all using only hands none using gloves; none wearing makeshift mask; none wearing goggles; all wearing shoes; all wearing clothing for harvesting; some wearing mask some washing; all using soap; all washing shoes; none washing feet; none washing hands; some washing body Jan-Dec 2 1,752
VNM-Cave-1 365 1,095 7,300 1.00 all using shovels; all using spades; all using brooms; all using only hands all using gloves; none wearing makeshift mask; none wearing goggles; all wearing shoes; all wearing clothing for harvesting; some wearing mask some washing; none using soap; none washing shoes; none washing feet; none washing hands; all washing body Jan-Dec 30 219,000

An exposure risk level was calculated from groupings of exposure variables: Guano Exposures, Collection Exposures, Personal and Protective Equipment (PPE) Exposures, and Water, Sanitation and Hygiene (WASH) Exposures. Each variable was assigned a relative exposure risk level: - Lowest risk: <0.2 - Low risk: 0.2-0.4 - Medium risk: 0.4-0.6 - High risk: 0.6-0.8 - Highest risk: >0.8.

Guano Exposures refer to environmental guano exposures, and are calculated from:

Collection Exposures are a function of the method that harvesters used to collect the guano - with riskier practices like using hands only to collect guano contributing to a higher exposure value:

PPE Exposures are protective factors related to the wearing of protective equipment and clothing:

Water, Sanitation, Hygiene factors refer to the availability and use of water and soap for washing and are a summary of the following:

The DRC site had the highest risk exposure value (0.75) attributed to riskier collection practices such as the use of hands to harvest guano instead of other implements. While Viet Nam Farm Site 2 had the lowest overall risk exposure value (0.44), guano is harvested for approximately 7,300 minutes per year per harvester. Though the Viet Nam Cave Site did not have a particularly high risk exposure value, guano is harvested for 65,700 minutes (1095 hours) per year at a total volume 7,300 kg of guano harvested.

Observations and Notes

Often, though water was not available directly on site for washing, harvesters washed their bodies in nearby rivers (Myanmar Cave Sites 1 and 2, Viet Nam Cave site).Another risky practice not explicitly covered in the questionnaire but derived from responses is eating lunch and snacks in the cave during breaks from harvesting guano.